Introduction

　　Diffractive multifocal element/lens of Beijing Homolaser Technology Co., Ltd allow a single incident beam to focus simultaneously at several focal lengths along the propagation axis. The number of foci is determined during the design according to the customer's application requirements. The figure below shows cross-section of processed sapphire using our 5-foci element and focusing lens，the intervals  basically keep consistent，energy irregularity is kept under 6%.

　　Besides，considering the convenience of application，we have produced a multifocal lens showed below，which allows for plug and play. Its internal structure consists of two part: multifocal element, focusing lens system wrapped up in stainless steel mechanical components. This lens finds its wide application in cutting transparent material，such as glass and sapphire. This manual is meant to aid the user's understanding of the functionality and considerations when using a diffractive multifocal element.

Working principle

　　The straightforward operational principle is using a collimated input beam (single mode or multi-mode), see below. The foci spot at the "zero" order refers to the refractive focal length of the lens being used. The other diffractive foci spots, orders +/-1,2,3…, appearing symmetrically around the refractive "zero" order, are in fixed numbers and  locations predetermined during the design of the DOE based on the customer's system requirements. An approximation of the distance between the foci spots can be described by the equation below:

　　fm：Focal Length for "m" diffractive order

　　ffocus：Focal Length of the refractive lens

　　fDOE：Focal Length of the diffractive lens

　　m：order of multi-focal spot，see below.

Multifocal lens

　　Aiming at transparent material cutting market，we released a multifocal cutting lens in a superb quality with accurate foci intervals and good energy uniformity. See our 11 foci lens parameters below.

　　The figure below is cross-section of dissected sapphire, with the surface roughness under 2um. Besides，we are capable to provide custom-tailored product covering multiple parameters including mechanical material, interface parameter, foci location, foci number, foci intervals.

Notification